Sexual transmission among men who have sex with men (MSM) accounted for the majority of incident HIV infections in the United States from 2006-2009. Preexposure chemoprophylaxis (PrEP) has been shown to reduce incident HIV infection by 44%, providing a substantial public health opportunity. Men on PrEP are required to have a least quarterly monitoring that includes laboratory testing for HIV and sexually transmitted infections, medication adherence and risk behavior assessments, and linkage with counseling, if needed. Currently, men must visit their providers for such services, a system that places a large burden on both providers and patients. If PrEP were to be scaled up to cover eligible, high-risk MSM in the United States, we estimate that millions of yearly patient visits would be required. The proposed research seeks to make PrEP scale-up more feasible, by developing a home-based monitoring and support system. A home-based system could have the benefits of decreasing patient and provider burdens, increasing patient willingness to undergo or remain or PrEP, facilitating the provision of PrEP care by non-specialists, and being a cost-saving program We propose to conduct qualitative, formative work to develop a home-based PrEP monitoring system that would consist of (1) specimen self-collection using mail-in kits; (2) online smartphone or SMS assessment of medication adherence and sexual behavior risk; and (3) video/telephone counseling support. After development of the PrEP monitoring and support system, we aim to pilot the program with a group of MSM currently on PrEP regimens in San Francisco, Boston and Atlanta.